<?php

/*
 * Copyright 2004-2005 The Apache Software Foundation or its licensors,
 *                     as applicable.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


require_once 'PHPCR/RepositoryException.php';
require_once 'PHPCR/observation/EventListener.php';
require_once 'PHPCR/observation/EventListenerIterator.php';


/**
 * The ObservationManager object.
 * <p>
 * Allows for the registration and deregistration of event listeners.
 *
 * @author Markus Nix <mnix@mayflower.de>
 * @package phpcr
 * @subpackage observation
 */
interface ObservationManager
{
    /**
     * Adds an event listener that listens for the specified <code>eventTypes</code> (a combination of one or more
     * event types encoded as a bit mask value).
     * <p>
     * The set of events can be filtered by specifying restrictions based on characteristics of the node associated
     * with the event. In the case of  event types <code>NODE_ADDED</code> and <code>NODE_REMOVED</code>, the node
     * associated with an event is the node at (or formerly at) the path returned by <code>Event.getPath</code>.
     * In the case of  event types <code>PROPERTY_ADDED</code>,  <code>PROPERTY_REMOVED</code> and
     * <code>PROPERTY_CHANGED</code>, the node associated with an event is the parent node of the property at
     * (or formerly at) the path returned by <code>Event.getPath</code>:
     * <ul>
     *   <li>
     *     <code>absPath</code>, <code>isDeep</code>: Only events whose associated node is at
     *     <code>absPath</code> (or within its subtree, if <code>isDeep</code> is <code>true</code>) will be received.
     *     It is permissible to register a listener for a path where no node currently exists.
     *   </li>
     *   <li>
     *     <code>uuid</code>: Only events whose associated node has one of the UUIDs in this list will be
     *     received. If his parameter is <code>null</code> then no UUID-related restriction is placed on events
     *     received.
     *   </li>
     *   <li>
     *     <code>nodeTypeName</code>: Only events whose associated node has one of the node types
     *     (or a subtype of one of the node types) in this list will be received. If his parameter is
     *     <code>null</code> then no node type-related restriction is placed on events received.
     *   </li>
     * </ul>
     * The restrictions are "ANDed" together. In other words, for a particular node to be "listened to" it must meet all the restrictions.
     * <p>
     * Additionally, if <code>noLocal</code> is <code>true</code>, then events generated by the session through which
     * the listener was registered are ignored. Otherwise, they are not ignored.
     * <p>
     * The filters of an already-registered <code>EventListener</code> can be changed at runtime by re-registering the
     * same <code>EventListener</code> object (i.e. the same actual Java object) with a new set of filter arguments.
     * The implementation must ensure that no events are lost during the changeover.
     *
     * @param listener an {@link EventListener} object.
     * @param eventTypes A combination of one or more event type constants encoded as a bitmask.
     * @param absPath an absolute path.
     * @param isDeep a <code>boolean</code>.
     * @param uuid array of UUIDs.
     * @param nodeTypeName array of node type names.
     * @param noLocal a <code>boolean</code>.
     * @throws RepositoryException If an error occurs.
     */
    public function addEventListener( EventListener $listener, $eventTypes, $absPath, $isDeep, $uuid, $nodeTypeName, $noLocal );

    /**
     * Deregisters an event listener.
     * <p>
     * A listener may be deregistered while it is being executed. The
     * deregistration method will block until the listener has completed
     * executing. An exception to this rule is a listener which deregisters
     * itself from within the <code>onEvent</code> method. In this case, the
     * deregistration method returns immediately, but deregistration will
     * effectively be delayed until the listener completes.
     *
     * @param listener The listener to deregister.
     *
     * @throws RepositoryException If an error occurs.
     */
    public function removeEventListener( EventListener $listener );

    /**
     * Returns all event listeners that have been registered through this session.
     * If no listeners have been registered, an empty iterator is returned.
     *
     * @return an <code>EventListenerIterator</code>.
     * @throws RepositoryException
     */
    public function getRegisteredEventListeners();
}

?>